feat(zns-importer): add ZNSImportService with tests and REST controller

- Created `ZnsImportService` to handle uploading, parsing, and persisting ZNS data from legacy `.zip` files.
- Introduced corresponding test cases in `ZnsImportServiceTest` for handling edge cases including imports and updates.
- Added REST controller `ZnsImportController` for initiating import jobs and retrieving their status.
- Defined `ZnsImportResult` data structure for reporting results of import operations.
- Established database configuration specific to ZNS importer for development profile.
- Updated utility libraries with `FixedWidthLineReader` for fixed-width string parsing.
- Refactored architecture by placing parser logic in `core:zns-parser` for reuse across backend and Compose Desktop app.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

core/zns-parser/build.gradle.kts

@@ -0,0 +1,30 @@
+plugins {
+  alias(libs.plugins.kotlinMultiplatform)
+  alias(libs.plugins.kotlinSerialization)
+}
+
+kotlin {
+  jvm()
+  sourceSets {
+    commonMain {
+      dependencies {
+        implementation(projects.core.coreDomain)
+        implementation(projects.core.coreUtils)
+
+        // Domänen-Modelle für das Parsing
+        implementation(projects.backend.services.clubs.clubsDomain)
+        implementation(projects.backend.services.persons.personsDomain)
+        implementation(projects.backend.services.horses.horsesDomain)
+        implementation(projects.backend.services.officials.officialsDomain)
+
+        implementation(libs.kotlinx.serialization.json)
+        implementation(libs.kotlinx.datetime)
+      }
+    }
+    commonTest {
+      dependencies {
+        implementation(libs.kotlin.test)
+      }
+    }
+  }
+}